Captive fastener with shoulder to prevent engagement of the screw head with the work



Dec. 17, 1963 w. 0. TAIT ETAL 3,114,405

CAPTIVE FASTENER mm SHOULDER TO PREVENT ENGAGEMENT OF THE SCREW HEADWITH THE WORK Original Filed Nov. 23, 1956 t?! 6 INVENTORS'.

WILLIAM 0. TA 17' BY IVORMANA.WILKI8 A rams/5y United, States Patent FCAPTIVE FASTENER WITH SHOULDER T0 PRE- VENT ENGAGEMENT OF THE SCREW HEADWITH THE WGRK William 0. Tait, Locust Valley, and Norman A. Wilkes,

. Plainview, N.Y., assignors to Reeves Instrument Corporation, GardenCity, N.Y., a corporation of New York Original application Nov. 23,1956, Ser. No. 624,071,

new Patent No. 2,967,557, dated Jan. 10, 1961. Divided and thisapplication Nov. 23, 1960, Ser. No. 71,214

3 Claims. (Cl. 151-69) This application is a division of applicationSerial No. 624,071, filed November 23, 1956, now Patent 2,967,557.

This invention relates to fastening devices, and more particularly tofasteners of the captivated type.

Captive fasteners are often used to secure electrical assemblies orunits within a housing or supporting frame. These units generallyconsist of a metal chassis on which electrical and mechanical componentsare mounted and a front panel attached to one side of the chassis. Theseassemblies may be installed within the housing or supporting frame byproviding guides attached to each side of the chassis which cooperatewith guides located within the supporting frame. The assemblies are slidinto the supporting'frame upon these guides. The fasteners are usuallyattached to the front panel near each side for engaging with suitablereceptacles affixed to the supporting frame. When the front panelismoved into position against the supporting frame, it is important thatthe fasteners be properly aligned so they will not be damaged T bystriking the frame or mating receptacles. Fasteners for this applicationshould be easily operated by hand,

should not mar the exposed surface of the front panel,

and should be readily removable from the panel without damaging eitherthe fastener or the panel.

In one type of prior art fastener the engaging element or stud ismaintained perpendicular to the panel by a retaining cup whichcompletely surrounds the stud. This cup, while keeping the stud in thedesired position for engagement with the receptacle, prevents operationof the fastener without a screw driver or other tool. fastener isusually secured to the panel by inserting it in an opening in the paneland then flaring over the lower part of the cup. Removal of the stud isprevented by flaring the top of the cup over the head of the stud. Suchfasteners cannot be readily removed from the panel and require the useof special tools in their assembly.

Other known captivated fasteners provide an accessible knurled knob topermit rotation by hand. Such fasteners, however, generally permit therotated element to bear against the panel or other stationary surfacewhen the fastener is engaged, thereby scratching or otherwise marringthe exposed panel surface after prolonged use. Furthermore, fasteners ofthis type are not provided with mews for maintaining their alignmentnormal to the panel surface when they are disengaged from theirreceptacle. A panel member having a plurality of such fasteners is notreadily attached to a cabinet, and considerable difficulty is oftenencountered in the alignment of all of the fasteners with theirreceptacles.

In accordance with our invention, a fasteneris provided which has itslongitudinal axis maintained normal to the panel member by a springsurrounding the stud. The spring is held in compression between a capattached to the shank of the stud and a cylindrical member, thecylindrical member telescoping inside the cap. The stud is provided withtwo sections of different diameters for forming a step for abutting andholding the panel member rigidly against a supporting frame. Thefastener is assembled and secured to the panel member by means The Y3,114,405 Patented Dec. 17,-1963 of a simple retaining ring which may bereadily removed and does not require the use of special tools forinstallation.

It is a principal object of this invention to provide an improvedfastening device which, when disengaged, is positioned with its axissubstantially normal to the panel member to which it is secured.

Another object is to provide a fastener that is relatively simple,attractive in appearance, and whose operation does not mar the exposedportion of the panel to which it is attached.

A further object is to provide a fastener which may be moved into exactalignment with its receptacle without damaging either the fastener orreceptacle.

Other objects and advantages of the invention will be apparent from thefollowing description, the appended claims, and the drawing of which:

FIGS. 1-3 illustrate three views of the improved fastener described inapplicants Patent 2,967,557.

. P16. 4 is a side view partially in section of the modified form of ourfastener described and claimed in this application.

FIG. 5 is a side view partially in section of another form of the.fastener described in applicants Patent 2,967,557.

FIG. 6 is a perspective view of the fastener attached toa panel member.

The fastener illustrated in FIGS. 1-3 comprises a stud 15 attached to ahollow cap 18, a spring 20, a sleeve 21, and a retaining ring 25. Thefastener is assembled to a panel member 10 by inserting the threaded endportion 13 of stud 15 through aperture 12 of panel 10 an permit somelateral displacement of stud 15. Since the fastener is held insubstantially the correct position by helical spring 2i it cannot bejammed between the panel and side wall. Moreover, spring 2%) permitssome angular movement of stud 15 and the stud can bemoved into alignmentwith receptacle 16 without damaging the threads of either the stud orthe receptacle. The threaded portion 13 of stud 15 is engaged with thethreaded portion of receptacle 16 by pressing cap 18 toward the paneland rotating the cap.

FIG. 4 shows the embodiment of this invention. In this form the annularcup is replaced by a cylindrical member 27 which surrounds the stud andis positioned between panel member 16 and helical spring 20. Thecylindrical member 27 is of sufficient length to assure that the openend of cylindrical cap 28 will overlap it when the stud is fullydisengaged from its receptacle. Stud 2 comprises two sections ofdifferent diameters. Stud section 30, having the greater diameter, issurrounded by spring 20 and the upper part of cylindrical member 27. Theother section 31 of stud 29 passes through aperture 12 in panel 16. Step32 resulting from the change in diameter of stud 29 is located outsideof hollow cap 2% so that when the fastener is fully engaged with itsreceptacle, step 32 will bear against the front surface of panel memberiii, thereby preventing contact of the edge of cap 28 with the panel.

In the fastener illustrated in FIG. 5, the hollow cylindrical cap 33comprises two portions, the portion 34 adjacent to the closed end havinga smaller inner diengaged, the annular member 36 telescopes within theportion of the hollow cap having the larger inner diameter and restsagainst step 37 which results from the change in inner diameter of thecap. The length of annular member 36 is made greater than the distancebetween the open end of portion 35 of cap 33 and step 37 to preventcontact of the edge of the cap with the front surface of the panel whenthe fastener is fully engaged.

FIG. 6 is a perspective view of the fastener which is typical of all ofthe forms presented since the outward appearance of each embodiment isalmost identical. The knurled cap is easily rotated by hand and whenpressed in toward the panel is prevented from marring the panel surfaceby one of the means previously described. The annular member or sleeveconceals the spring and stud, thus contributing to the attractiveappearance of the fastener while providing a bearing surface against thepanel.

The fastener components may be held together before installation in thepanel member by the same retaining ring that is used to secure thefastener to the panel after installation. The retaining ring would, ofcourse, be removed prior to insertion of the stud in the panel apertureand then replaced after insertion of the stud.

The fastener is easily manufactured, assembled, and attached to thepanel member. Since simple retaining means may be used, flaring orsimilar operations which would make it difiicult if not impossible toremove the fastener from the panel without damage are eliminated. When anumber of fasteners are used to attach a panel to a supporting frame nodifficulty is encountered in engaging them simultaneously since each ofthe fasteners is prealigned and may be moved smoothly into itsreceptacle.

As many changes could be made in the above construction and manydifferent embodiments of this invention could be made without departingfrom the scope thereof, it is intended that all matter contained in theabove description or shown in the accompanying drawing shall beinterpreted as illustrative and not in a limiting sense.

What is claimed is:

l. A captive fastener adapted for rigidly attaching a panel member to asupporting frame, said supporting frame including receptacle means forengaging said fastener, comprising in combination, a hollow cap havingan open end and a closed end, a stud having first and second portions ofdifferent diameters, the stud portion having the larger diameter beingdirectly attached to the inner surface of the closed end of said hollowcap, the stud portion having the smaller diameter extending outside saidhollow cap, the length of the larger diameter portion of said stud beingslightly longer than the depth of said hollow cap, helical spring meanssituated within said hollow cap and surrounding the larger diameterportion of said stud, a cylindrical member having a uniform outerdiameter surrounding the larger diameter portion of said stud andtelescoping within said hollow cap, said cylindrical member compressingsaid helical spring be tween the inner surface of the closed end of saidhollow cap and one end of said cylindrical member by the insertion ofthe smaller diameter portion of said stud through an aperture in saidpanel member, the aperture in said panel member being larger than thesmaller diameter portion of said stud and smaller than the largerdiameter portion of said stud, the other end of said cylindrical memberabutting directly against the front surface of said panel member,retaining means attached to and carried by the smaller diameter portionof said stud at a fixed position thereon, said retaining means having aportion protruding from said stud and abutting directly against the rearsurface of said panel member for bolding the fastener captive to saidpanel member when the fastener is disengaged, the length of said helicalspring means being sufficient to exert a force between the inner surfaceof the closed end of said hollow cap and said cylindrical member tomaintain the other end of said cylindrical member directly against thefront surface of said panel when the fastener is disengaged, andengaging means alfixed near the end of the smaller diameter portion ofsaid stud for engaging said receptacle means, said engaging means beingadapted to engage said receptacle means upon rotation of said fastenerfor advancing the step resulting from the change in diameter of saidstud firmly against the front surface of said panel to rigidly hold saidpanel member against said supporting frame.

2. The captive fastener as defined by claim 1 wherein the length of saidcylindrical member is greater than the distance between the open end ofsaid hollow cap and the front surface of said panel member when thefastener is disengaged.

3. The captive fastener as defined by claim 1 wherein said engagingmeans affixed near the end of the smaller diameter portion of said studcomprises a threaded region.

References Cited in the file of this patent UNITED STATES PATENTS1,419,974 McLaughlin June 20, 1922 2,826,231 Alden Mar. 11, 1958 FOREIGNPATENTS 534,439 England Mar. 6, 1941

1. A CAPTIVE FASTENER ADAPTED FOR RIGIDLY ATTACHING A PANEL MEMBER TO ASUPPORTING FRAME, SAID SUPPORTING FRAME INCLUDING RECEPTACLE MEANS FORENGAGING SAID FASTENER, COMPRISING IN COMBINATION, A HOLLOW CAP HAVINGAN OPEN END AND A CLOSED END, A STUD HAVING FIRST AND SECOND PORTIONS OFDIFFERENT DIAMETERS, THE STUD PORTION HAVING THE LARGER DIAMETER BEINGDIRECTLY ATTACHED TO THE INNER SURFACE OF THE CLOSED END OF SAID HOLLOWCAP, THE STUD PORTION HAVING THE SMALLER DIAMETER EXTENDING OUTSIDE SAIDHOLLOW CAP, THE LENGTH OF THE LARGER DIAMETER PORTION OF SAID STUD BEINGSLIGHTLY LONGER THAN THE DEPTH OF SAID HOLLOW CAP, HELICAL SPRING MEANSSITUATED WITHIN SAID HOLLOW CAP AND SURROUNDING THE LARGER DIAMETERPORTION OF SAID STUD, A CYLINDRICAL MEMBER HAVING A UNIFORM OUTERDIAMETER SURROUNDING THE LARGER DIAMETER PORTION OF SAID STUD ANDTELESCOPING WITHIN SAID HOLLOW CAP, SAID CYLINDRICAL MEMBER COMPRESSINGSAID HELICAL SPRING BETWEEN THE INNER SURFACE OF THE CLOSED END OF SAIDHOLLOW CAP AND ONE END OF SAID CYLINDRICAL MEMBER BY THE INSERTION OFTHE SMALLER DIAMETER PORTION OF SAID STUD THROUGH AN APERTURE IN SAIDPANEL MEMBER, THE APERTURE IN SAID PANEL MEMBER BEING LARGER THAN THESMALLER DIAMETER PORTION OF SAID STUD AND A SMALLER THAN THE LARGERDIAMETER PORTION OF SAID STUD, THE OTHER END OF SAID CYLINDRICAL MEMBERABUTTING DIRECTLY AGAINST THE FRONT SURFACE OF SAID PANEL MEMBER,RETAINING MEANS ATTACHED TO AND CARRIED BY THE SMALLER DIAMETER PORTIONOF SAID STUD AT A FIXED POSITION THEREON, SAID RETAINING MEANS HAVING APORTION PROTRUDING FROM SAID STUD AND ABUTTING DIRECTLY AGAINST THE REARSURFACE OF SAID PANEL MEMBER FOR HOLDING THE FASTENER CAPTIVE TO SAIDPANEL MEMBER WHEN THE FASTENER IS DISENGAGED, THE LENGTH OF SAID HELICALSPRING MEANS BEING SUFFICIENT TO EXERT A FORCE BETWEEN THE INNER SURFACEOF THE CLOSED END OF SAID HOLLOW CAP AND SAID CYLINDRICAL MEMBER TOMAINTAIN THE OTHER END OF SAID CYLINDRICAL MEMBER DIRECTLY AGAINST THEFRONT SURFACE OF SAID PANEL WHEN THE FASTENER IS DISENGAGED, ANDENGAGING MEANS AFFIXED NEAR THE END OF THE SMALLER DIAMETER PORTION OFSAID STUD FOR ENGAGING SAID RECEPTACLE MEANS, SAID ENGAGING MEANS BEINGADAPTED TO ENGAGE SAID RECEPTACLE MEANS UPON ROTATION OF SAID FASTENERFOR ADVANCING THE STEP RESULTING FROM THE CHANGE IN DIAMETER OF SAIDSTUD FIRMLY AGAINST THE FRONT SURFACE OF SAID PANEL TO RIGIDLY HOLD SAIDPANEL MEMBER AGAINST SAID SUPPORTING FRAME.